Hello! I recently purchased a 2015 GL450 4Matic off auction. When I first started it up, I had radio sound for about 3 seconds then nothing since for the near month I have had it. I plug my phone into the center console and it is the only way I can get audio. I have reset the head unit, software, and even made sure my phone is up to date. I also noticed the volume severely lags when I try to adjust it, I need to turn the volume dial 2 full turns before the audio starts to go up or down. Pretty much everything else electronically works in the car and the sound is amazing when my phone is plugged in. I would just like the convenience of bluetooth audio.